Answer: The missing side is 6mm.
Step-by-step explanation: For 18mm to drop to 12mm, it dropped 6mm. Therefore, the missing side was 12mm, and if you drop 6mm, you get 6mm.
We need to simplify the expression:

Now, we know that we can resolve the exponents of the variables with the like terms only and we can multiply the coefficients independently:
Now,

On simplifying the above expression we get:




So the simplified form of the expression
.
No, the 2 lines can never ever be both parallel and perpendicular if I'm not mistaken. This is because a set of parallel lines will never touch each other at all. However perpendicular lines are two lines that meet up to get an angle of 90. You cannot have two lines that never touch and touch at the same time.
Answer:
The guard should be positioned at the safe
Step-by-step explanation:
The night watchmen should be positioned to guard whichever place gives the highest expected value to the thief.
The expected value of robbing the safe is:

The expected value of robbing the cash register is:

Therefore, the guard should be positioned at the safe since it yields a higher expected value to the thief in case he tries to rob it.